Add "Download All in ZIP" feature for session downloads

Introduce automatic ZIP file creation and management for session-based downloads.
- Server: Add endpoints to serve and provide info about session ZIPs; VideoService now updates ZIP after each MP3 download with user-friendly filenames.
- Client: Add "Download All in ZIP" button with loading state and ZIP info; trigger browser download via JS interop; responsive and styled UI.
- API: Extend service interfaces for ZIP download/info; add SessionZipInfo model.
- Docs: Update SESSION_MANAGEMENT.md with ZIP workflow, endpoints, and UX details.
- Robust error handling and logging throughout.

TuneRipper.Api/Program.cs

@@ -66,9 +66,20 @@ app.MapGet("/", (IWebHostEnvironment env) => new
         get_result = "/api/video/result/{jobId}",
         download = "/api/download/{jobId}",
         download_by_session = "/api/download/{sessionId}/{jobId}",
+        download_session_zip = "/api/download/zip/{sessionId}",
+        session_zip_info = "/api/download/zip/info/{sessionId}",
+        session_create = "/api/session/create",
+        session_validate = "/api/session/validate/{sessionId}",
         static_files = "/downloads/{fileName}",
         openapi = "/openapi/v1.json"
     },
+    features = new
+    {
+        session_management = true,
+        automatic_zip_creation = true,
+        session_based_organization = true,
+        backward_compatibility = true
+    },
     testing = new
     {
         httpFile = "Use api-tests.http to test endpoints",
@@ -88,5 +99,6 @@ app.Logger.LogInformation("?? Health check: /api/health");
 app.Logger.LogInformation("?? API info: /");
 app.Logger.LogInformation("?? Static files served from: /downloads/*");
 app.Logger.LogInformation("?? Session-based downloads supported");
+app.Logger.LogInformation("?? Automatic ZIP file creation enabled");
 
 app.Run();